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June 24, 2026
Joe Averill
17 mins
The 31 March 2026 deadline to file a Check against the 2023 rating list has passed. If you acted before that date, your Check is registered. If you didn't — the reality for most office tenants — the 2023 list is now closed for all but a narrow category of exceptional cases. New bills landed on 1 April 2026. The five-multiplier system is live. A 3-month window to challenge your new rateable value on the 2026 list started on 1 April and is running right now.
This article covers the 2026 business rates revaluation in full: where the calendar stands today, the new multipliers as they apply specifically to offices, the transitional relief mechanics, the Check stage abolition, and what you need to do before that Challenge window closes. If your office bill landed in April and you haven't yet verified what the VOA has on record for your property, that is the single most valuable hour you can spend this month.
The Non-Domestic Rating Act 2023 fixed a three-yearly revaluation cycle. The 2026 cycle was the first under that statutory timetable.
Two facts deserve particular attention. First, the antecedent valuation date is 1 April 2024 — which means your new rateable value reflects market rents at that date, not today's market. For many central London offices, April 2024 rents were already elevated; for some secondary markets, they were below where prime is now. Whether your 2026 RV is fair depends on which direction the market has moved since April 2024 and whether the VOA has measured your floor correctly.
Second, the 3-month Challenge deadline is hard. Missing it does not close off the entire 2026 list — you can file at any point while the list runs, through to March 2029 — but the window immediately after a new list is published is when factual errors are most efficiently caught. The longer you wait, the more a queried valuation looks like retrospective challenge rather than legitimate dispute.
The Non-Domestic Rating (Multipliers and Private Schools) Act 2025 (Royal Assent 3 April 2025, effective 1 April 2026) replaced the single-rate multiplier with five separate rates. Before you can model what your bill should be, you need to know which one applies. For offices, the answer turns entirely on rateable value — offices are never Retail, Hospitality and Leisure hereditaments, so the two lower RHL multipliers do not apply to you.
The RHL multipliers (38.2p small business; 43.0p standard) appear prominently in Budget commentary because they were the largest political concession to the hospitality industry. They play no part in calculating your office bill. Any rates agent who presents you with the 38.2p or 43.0p rates in the context of your office costs is, at best, confused.
The 50.8p high-value multiplier is the figure that has received least attention and causes the largest shock. It is 2.8p above the standard multiplier. On a £700,000 rateable value prime City office that is an additional £19,600 per year — before the 1p Transitional Supplement is added. A 30,000 sq ft premium building in the City is plausibly well into the £500,000+ RV band, putting it inside this top tier. If your office is in a recognised prime submarket — EC2/EC3 core, Mayfair, St James's, Canary Wharf — verify your RV against the £500,000 threshold before assuming you are on the standard rate.
The full mechanics of the new 5-multiplier business rates system — including how the five bands interact with different property types and the policy rationale behind the high-value tier — are covered in the companion piece.
BRIL 5/2025, which confirmed the Budget multiplier package, introduced a detail that attracted almost no press coverage: a 1p supplement added to the multiplier for 2026/27 only, applying to ratepayers who are not receiving Transitional Relief 2026 and not inside the Supporting Small Business scheme.
In plain terms: if your rates bill has increased materially enough to be captured by Transitional Relief phasing, you are protected from the supplement. If your increase is small enough to sit below the TR cap, or if your liability moved down or held flat, the 1p hits.
On a £250,000 rateable value mid-sized office paying the standard rate, the effective multiplier for 2026/27 is 49.0p rather than 48.0p — a bill of £122,500 rather than £120,000. On a £700,000 RV prime office outside Transitional Relief, it costs an additional £7,000 for the year. One year only; the supplement drops from 1 April 2027.
The mechanics of transitional relief 2026 — which properties are inside the cap, how the three-year phase-in works, and which occupiers the supplement hits hardest — are set out fully in the supporting article.
Transitional Relief 2026 phases in bill increases over three years to 2028/29. This protects occupiers whose rateable value has risen sharply — the relief caps how much your bill can grow each year, so you do not face the full increase on day one.
What changed materially from earlier revaluation cycles: downward adjustments take effect immediately on 1 April 2026. If the 2026 revaluation reduced your RV, you see the benefit in full from the first April bill. There is no phasing of decreases. This is a genuine change for office occupiers in markets where RVs have softened — secondary City space, some regional CBDs where supply has increased — and it is worth quantifying before accepting the first bill as definitive.
Supporting Small Business 2026 (SSB) caps the annual increase at the higher of £800 or the transitional cap for eligible ratepayers. It has been extended to businesses that were previously receiving 2025/26 Retail, Hospitality and Leisure relief and lost it on 1 April 2026. For most pure office tenants, SSB is not in scope — but if your property has mixed retail and office use, check eligibility before paying the unrelieved bill.
The SBRR grace period extension (in force from 27 November 2025) means that businesses taking on a second property on or after that date retain Small Business Rate Relief on their original property for three years instead of one. If you have recently opened a second office and were expecting to lose SBRR on your first, re-check your position.
The single most leveraged action you can take in the first weeks of the 2026 list is to verify the Valuation Office Agency's factual record of your property. Errors in the factual record translate directly into inflated rateable values, and the VOA's inspection of your building may be years old.
What the factual record contains:
- The hereditament boundaries — critical where your demise has changed since the previous inspection, or where floors have been reconfigured.
- Gross internal area (GIA) broken down by use type: primary office space, ancillary areas, plant rooms, storage, car parking spaces. Different use types attract different per-sq-ft rates in the VOA's valuation scheme.
- The areas and values of any tenant improvements completed since 1 April 2024 — the antecedent valuation date — which may qualify for improvement relief.
Where errors most often appear in office hereditaments:
- The recorded floor area comes from a historic VOA inspection that pre-dates a fit-out, demise split, or floor reconfiguration. A 500 sq ft discrepancy on a 10,000 sq ft floor, at £50/sq ft of rateable value, represents £25,000 in excess annual liability over the life of the list.
- Plant rooms, shower rooms, and server rooms that should be valued at ancillary rates are recorded as primary office space.
- Mezzanines installed or removed since the previous valuation appear in the historic record.
- Car parking spaces counted separately as standalone hereditaments are also being absorbed into the floor-area measurement.
- Two previously separate floors that have been merged in occupation but not in the rating list — taxed at two lower-RV rates rather than one combined rate. The combined valuation may actually be lower.
You can obtain the detailed valuation yourself, free, at gov.uk/correct-your-business-rates. No agent is required to access the factual record or request it. This is the starting point: read what the VOA has on record, check it against your floor plans, and identify any discrepancy before paying a quarterly bill based on incorrect data.
For a full breakdown of how the VOA values a standard London office — the floor-by-floor methodology, the treatment of ancillary areas, and how comparable rental evidence at the antecedent valuation date is applied — the dedicated supporting article covers the valuation methodology in detail.
Once you have the VOA's confirmed rateable value and have verified the factual basis, the gross liability calculation is straightforward. The model the VOA and billing authorities use is:
Rateable value × applicable multiplier (+ 1p supplement if not in TR/SSB) = gross liability before reliefs.
Three worked examples using the 2026/27 multipliers:
Now compare the gross 2026/27 liability against what you actually paid in 2025/26 (the figure from your last bill, gross of any 2024/25 transitional relief). The gap tells you three things: whether your bill has increased or decreased; whether Transitional Relief 2026 may be phasing the increase; and whether the 1p supplement is in your calculation.
The point at which this exercise stops being mechanical is when the rateable value driving the calculation is wrong. A VOA area error, an unrecorded demise change, or a mislabelled use type does not show on the multiplier line — it shows on line one. Every subsequent calculation built on a wrong RV is wrong at source. Verify the factual record before accepting the gross figure.
The Check Challenge Appeal process has changed materially for the 2026 list. Under the 2023 list, ratepayers could file a Check at any point during the life of the list, and the Check itself was a factual investigation that preceded any Challenge to the valuation. On the 2026 list, the Check stage has been removed. The process now goes directly to Challenge.
What that means in practice:
- If you believe the VOA's factual data is wrong, you notify them under the Duty to Notify regime (see below) rather than filing a Check.
- If you believe the valuation — the per-sq-ft rate applied to correct factual data — is wrong, you file a Challenge directly.
- The Challenge window on a new list is 3 months from the date the list took effect: for the 2026 list, that is 3 months from 1 April 2026.
You can still file a Challenge after that window. But the initial 3-month period is when factual errors and valuation disputes on the new list are most efficiently surfaced and resolved. Waiting until 2027 or 2028 to question a 2026 valuation is not prohibited, but it concentrates the bill you have already paid into years that cannot be recovered.
The full procedure — grounds for Challenge, how to file, what evidence the VOA requires, and the tribunal route if Challenge fails — is covered in the 3-month Challenge window explained.
The Non-Domestic Rating Act 2023 introduced the Duty to Notify regime, phasing in from 1 April 2026 and fully mandated by 1 April 2029. It replaces the old Check stage with a continuous real-time compliance obligation.
Under the regime, you have two duties:
The enforcement bite: access to Challenge becomes conditional on Duty to Notify compliance once the regime is fully mandated on 1 April 2029. Ratepayers who fall behind on their notification obligations lose the right to contest their valuation. You cannot argue that the VOA has valued your floor incorrectly if you have not been keeping them informed of what the floor actually is.
The penalties for non-compliance are substantive. Providing false data attracts up to 3% of rateable value plus £500, with criminal sanctions for knowing or reckless falsehoods. Failure to comply with a notification obligation attracts the greater of 2% of rateable value and £900, plus £60 per day as a continuing penalty. On a £700,000 RV office, a false-data penalty reaches £21,500 in a single event.
For the operational compliance playbook — what systems multi-property occupiers need, how to structure an internal notification process, and what the phase-in period actually requires before full mandation — the full treatment is in the Duty to Notify.
For most occupiers: no. The 31 March 2026 deadline was the cut-off.
The narrow exceptions are:
- Material change of circumstances that affected the property's value during the life of the 2023 list and was not captured before the deadline. The change must be one that occurred within the 2023 list period — not historical information that simply wasn't filed in time.
- Manifest errors in the VOA's factual data that resulted in an overstatement of rateable value throughout the 2023 list period.
Both routes are genuinely narrow. They require documented evidence of a specific change or a specific factual error, not a general objection to the 2023 valuation level. If you believe you have grounds under either, take professional advice immediately — the exceptional-circumstances route is not self-service, and the longer you wait, the harder the argument becomes.
For the vast majority of office tenants, the actionable position is the 2026 list. That is where the 3-month window is live, where the new multipliers are biting, and where factual records can still be checked and corrected within the current Challenge process.
The 31 March 2026 deadline and the new 3-month Challenge window create exactly the pressure that rogue rating agents exploit. A cold call promising a large reduction on your new rateable value, backed by an upfront fee and a long lock-in contract, is a pattern the VOA has documented formally since its January 2024 agent standards publication.
Three things the legitimate rating profession has that rogue agents do not:
- Membership of RICS, IRRV (Institute of Revenues, Rating and Valuation), or RSA (Rating Surveyors' Association) — the only three bodies that hold members to the joint Rating Consultancy Code of Practice.
- Accountability under that Code for the accuracy of representations made to the VOA on your behalf.
- The consequence that any penalty for inaccurate data submitted to the VOA sits with you, the ratepayer — not the agent. A rogue agent who inflates a claim to justify their fee and is found out leaves you with the penalty exposure and them with the fee.
The free route exists. You can view the VOA's factual record of your property and file a Challenge yourself at gov.uk/correct-your-business-rates. No professional engagement is required for the initial factual review. For a contested valuation, where comparable rental evidence needs analysing and the per-sq-ft rate needs arguing down, professional input earns its cost. For simply checking whether the VOA has the right floor area on record, it does not.
The full framework — how to evaluate a rating agent, the red flags to avoid, and how RICS, IRRV and RSA membership actually constrains conduct — is in how to choose a business rates agent.
The practical checklist, in order:
Step 1 — Obtain your 2026 rateable value from the VOA. Log in to gov.uk/correct-your-business-rates. Confirm the rateable value that appears on your April bill matches the VOA's current record.
Step 2 — Verify the factual data. Request the detailed valuation. Check the recorded gross internal area against your floor plans. Confirm use-type classifications for ancillary areas. Note any discrepancies.
Step 3 — Identify your multiplier band. Is your RV below £51,000 (43.2p), £51,000–£499,999 (48.0p), or £500,000 or above (50.8p)? Check whether the 1p supplement applies by confirming whether you are inside Transitional Relief 2026 or SSB 2026.
Step 4 — Run the four-line model. RV × multiplier (+ 1p if outside TR/SSB) = gross liability. Compare against your 2025/26 bill. Does the number on your April statement match?
Step 5 — Screen for reliefs. Transitional Relief 2026; SSB 2026; SBRR (if RV below the thresholds and you hold one property, or two from 27 November 2025 forward); improvement relief if capital works were completed after 1 April 2024; empty rates if any part of your premises is vacant.
Step 6 — Decide on a Challenge. If the factual data is wrong, correct it via the Duty to Notify process now in force. If the valuation — the per-sq-ft rate applied to correct data — is wrong, file a Challenge. The 3-month window from 1 April 2026 closes on 30 June 2026. If you are past that date, a Challenge is still open; it just sits outside the initial window.
Step 7 — Connect the rates bill to your next lease event. If your office lease is due for renewal or review in the next two to three years, the 2026 revaluation directly affects the total occupancy cost argument. A material rates increase compounds the renewal negotiation; a decrease — where the market has moved against the landlord's position since April 2024 — strengthens it. The rates revaluation and the lease renewal are rarely planned together; they almost always land in the same window.
Step 6 has a hard date. The rest does not expire — but every month of overpayment on an incorrect rateable value is a month of rates expenditure you will not recover.
Want to find your next leased, managed or serviced office space to rent? Book a call with our team today.
